Check the
appropriate box to designate the rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☐ Rule 13d-1(c)

☒
Rule 13d-1(d)

*

The remainder of this cover page shall be filled out for a reporting persons initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information
which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover
page shall not be deemed to be filed for the purpose of Section 18 of the Securities Exchange Act of 1934 (Act) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions
of the Act (however, see the Notes).

Deidre Cowan, Mr. Cowans spouse, beneficially owns 3,158,509 Ordinary Shares,
consisting of the 3,158,509 Ordinary Shares held of record by QBDG. Mrs. Cowan is the sole shareholder of QBDG and, in such capacity, exercises sole voting and dispositive power over the shares held of record by QBDG.

Paul Cowan beneficially owns 3,496,565 Ordinary Shares, consisting of (a) 3,158,509 Ordinary Shares beneficially owned by Mr. Cowans
spouse, Deidre Cowan, who exercises sole voting and dispositive power over the Ordinary Shares held of record by QBDG, (b) 58,145 Ordinary Shares held directly by Mr. Cowan, (c) 11,667 Ordinary Shares Mr. Cowan may acquire upon the exercise of
options to purchase Ordinary Shares at $11.92 per Ordinary Share, which options are exercisable as of the date of this filing, (d) 123,431 Ordinary Shares Mr. Cowan may acquire upon the exercise of options to purchase Ordinary Shares at $3.29 per
Ordinary Share, which options are exercisable as of the date of this filing, (e) 90,000 Ordinary Shares Mr. Cowan may acquire upon the exercise of options to purchase Ordinary Shares at $8.00 per Ordinary Share, which options are exercisable as of
the date of this filing, (f) 23,334 Ordinary Shares Mr. Cowan may acquire upon the exercise of options to purchase Ordinary Shares at $15.17 per Ordinary Share, which options are exercisable as of the date of this filing, and (g) 31,479 Ordinary
Shares Mr. Cowan may acquire upon the exercise of warrants at $5.80 per Ordinary Share, which warrants are exercisable as of the date of this filing.

The Ordinary Shares beneficially owned by Mr. Cowan do not include (a) 42,000 Ordinary Shares Mr. Cowan may
receive upon the vesting of Multi-year Performance Based Restricted Share Units (MRSUs), which MRSUs will vest upon the Ordinary Shares achieving a volume weighted average market price (VWAP) of $60.00 per Ordinary Share for
20 consecutive trading days during the period April 1, 2018 to December 31, 2018, (b) 60,000 Ordinary Shares Mr. Cowan may receive upon the vesting of MRSUs, which MRSUs will vest upon the Ordinary Shares achieving a VWAP of $22.00 per share for 20
consecutive trading days during the period April 1, 2019 to December 31, 2019, (c) 11,666 Ordinary Shares Mr. Cowan may acquire upon the exercise of options to purchase Ordinary Shares at $15.17 per Ordinary Share, which options will become
exercisable on May 20, 2017, (d) 42,000 Ordinary Shares Mr. Cowan may receive upon the vesting of MRSUs, which MRSUs will vest upon the Ordinary Shares achieving a VWAP of $40.00 per Ordinary Share for 20 consecutive trading days during the period
April 1, 2018 to December 31, 2018, (e) 23,333 Ordinary Shares Mr. Cowan may acquire upon the exercise of options to purchase Ordinary Shares at $11.92 per Ordinary Share, of which options will become exercisable in two equal annual installments on
June 1, 2018, and (f) 50,000 Ordinary Shares Mr. Cowan may acquire upon the exercise of options to purchase Ordinary Shares at $7.58 per Ordinary Share, which options will become exercisable in three equal installments beginning on May 24, 2018.

The percentage of Ordinary Shares beneficially owned by each Reporting Person is based on a total of 45,588,091 Ordinary Shares of the
Issuer outstanding as of February 5, 2017, as reported on the Issuers Quarterly Report on Form 10-Q for the quarter ended December 31, 2017.

(b)

Percent of class:

See Item 11 of each cover page.

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote:

See Item 5 of each cover page.

(ii)

Shared power to vote or to direct the vote:

See Item 5 of each cover page.

(iii)

Sole power to dispose or to direct the disposition of:

See Item 5 of each cover page.

(iv)

Shared power to dispose or to direct the disposition of:

See Item 5 of each cover page.

Item 5.

Ownership of Five Percent or Less of a Class:

Not applicable.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person:

Not applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person:

Not applicable.

Item 8.

Identification and Classification of Members of the Group:

Not applicable.

Item 9.

Notice of Dissolution of Group:

Not applicable.

Item 10.

Certifications:

Not applicable.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true,
complete and correct.

February 22, 2018

QUOTIENT BIODIAGNOSTICS GROUP LIMITED

By:

/s/ Deidre Cowan

Deidre Cowan

Director

PAUL COWAN

/s/ PAUL COWAN

DEIDRE COWAN

/s/ DEIDRE COWAN

EXHIBIT INDEX

Exhibit 99.1

Joint Filing Agreement (The Joint Filing Agreement is incorporated by reference to Exhibit 99.1 to the Schedule 13G filed by the Reporting Persons with the Securities and Exchange Commission on February 12,
2015).